This invention relates to baseball pitching machines. More particularly this invention relates to an improved pitching machine having ball grips positioned to match a grip used by a pitcher. A top side portion of the ball is held by two grips; the other bottom side portion of the ball is held by a single grip. This arrangement facilitates laterally spinning a ball; and coupled with a floating wheel which more consistently squeezes varying ball diameters, results in a ball pitching apparatus which can throw varying pitches more consistently within the strike zone.
U.S. Pat. No. 4,197,827 issued to T. L. Smith on Apr. 15, 1980 discloses a ball pitching apparatus which utilizes a spinning upper and lower wheel. Each wheel utilizes an elastomer peripheral concave surface to grip a ball which is accelerated when it is passed between the spinning wheels. The ball is accelerated to 60 plus mph in approximately 50 milliseconds as it passes between the wheels. One problem with the apparatus is that with varying ball diametersxe2x80x94balls vary in diameter as much as {fraction (1/10)}xe2x80x3xe2x80x94different balls are gripped or squeezed with varying force; and consequently, they are accelerated between the wheels to widely varying speeds. Another problem with T. L. Smith""s apparatus is that these machines are very time consuming to set up and tune to pitch in the strike zone. After a machine has been set up and tuned its setting is not varied. In order to pitch different curves and speeds it is necessary to set up several different ball pitching apparatuses. One for each type of pitch desired. One problem with this is that a batter is able to consistently anticipate the same type of pitch, say fast balls while practicing batting before a particular machine.
Yet another problem with the existing pitching apparatuses is that they are excessively heavy. The apparatuses use two brushed DC motors which each rotate on an end portion of one of the upper and lower wheel shafts. There is a repeated and enormous twisting moment on the shafts as balls are instantaneously accelerated to speeds approaching 100 mph. The frame carrying the motors, the shafts and the bearings must all be very substantial to remain in precise alignment for accurate pitches with repeated heavy load. In practice the heavy machines are set up, tuned and never moved. The large space around them and extending to the batter is dedicated to use with the pitching apparatus.
It is an object of this invention to disclose a ball pitching apparatus having ball grips positioned to match a grip used by a pitcher. A top side portion of the ball is held by two grips; the other side portion of the ball is held by a single grip. A baseball is not quite spherical. The seams on the leather casing extend outwardly from its spherical inner portion approximately xe2x85x9xe2x80x3. When a pitcher grips a ball he holds the ball only with his index finger, his long finger, and his thumb. He aligns the end portions of his fingers over and behind the seams to better spin the ball so that its trajectory is curved. The three point grip best holds and supports a non spherical ball. If the ball is squeezed more tightly between his long finger and his thumb than between his index finger and his thumb, it will have more lateral spin. The resulting pitch will have more lateral curve.
In comparison a non spherical ball held by two points on opposite sides of its top portion and by two points on opposite sides of its bottom portion is not as well held and supported. It is like a 4 legged table on a non flat floor. Unlike a three legged table it may rock. And further when the ball is held by two gripping points on its bottom side portionxe2x80x94even if a seam falls directly beneath one of its top gripping points so that one lateral side of the ball is more squeezed than the otherxe2x80x94the ball will not spin laterallyxe2x80x94the bottom side portion of the ball, from one gripping point to the other, must turn at the same speed. The applicant has found that he may predictably vary lateral curve on pitches by loading the seams of the ball differently with respect to the gripping points.
It is an object of this invention to disclose an apparatus which will grip and squeeze marginally varying diameters of balls with uniform force. Different baseballs have different coverings and seams, used balls are softer than new balls, and diameters of gripped and squeezed balls may vary as much as {fraction (1/10)}xe2x80x3. When one considers that the ball must be accelerated to as much as 100 mph in a brief 50 milliseconds as it passes and slips between two fast spinning wheels, how hard it is squeezed, and how much it slips, is critical to its acceleration. A mechanism which automatically squeezes balls of varying diameters with consistent force can accommodate and uniformly pitch new and used balls, as well as balls having different seam and overall dimensions consistently with adequate accuracy. This is a significant practical advantage.
It is yet a further object of this invention to disclose a baseball pitching apparatus which utilizes wheels having brushless internal DC drive motors. These motors may be more accurately controlled for speed than DC motors having brushes. Additionally, this arrangement loads a relatively short motor shaft centrally. Compared to a cantilevered loading arrangement the motor shaft and bearings may be much lighter and still adequately support repeated and substantial loading moment as balls are instantaneously accelerated to as much as 100 mph.
It is a final object of this invention to disclose a ball pitching which may not only more accurately pitch strikes, but which can pitch strikes having varying positions within the strike zone. With the use of a microprocessor which memorizes and controls different frame rotational positions, as well as wheel rotational speeds, it is possible to replace multiple pitching machines, each used to throw substantially different pitches, with a single machine.
One aspect of this invention provides for an improvement in a ball pitching apparatus having; an upper and lower wheel, said wheels rotating on substantially parallel shafts and having generally aligned and spaced rims carrying peripheral ball gripping means; independent speed controlled drive means for rotating each of the wheels in opposite directions; a ball feeder for feeding the ball between the spaced rims so that the ball will be gripped therebetween and accelerated in a trajectory generally tangential to the rims it is gripped between; a head frame carrying the wheels, drive means, and ball feeder; and, a stand carrying the head frame. The improvement comprises: a singular gripping band on one wheel and two spaced gripping bands on the other wheel so that the ball contacts and is gripped by a single contact area on one side of the ball and two separate contact areas on an opposite side of the ball. The ball is held and gripped by three discrete points on its peripheral surface.
Another aspect of this invention, in a pitching apparatus as described above, provides for the improvement comprising: one of the wheels rotating on a shaft biased towards the other wheel so that the ball to be pitched will be gripped with a similar force regardless of ball diameter variations, ball seam positioning between the wheels, or ball hardness.
Yet another aspect of this invention, in a pitching apparatus as described above, provides for the improvement comprising: wheel drive means which are DC motors internally positioned within the wheel so that the shafts and bearings in the motors are directly and radially loaded when the ball is gripped and accelerated and so that the frame, shafts, and bearings may be substantially lighter than if they need be designed to maintain the wheels in precise rigid alignment while bearing a repeated cantilevered load arising from the ball""s acceleration. This results in a lighter and more compact frame head, which in turn facilitates portability, and rotational movement and control of the frame head on the stand.